metabolism article 39 animal 18 male 18 Support, Non-U.S. Gov't 17 enzymology 17 Porphyrins 16 Male 15 mouse 15 porphyrin 15 Mice 13 biosynthesis 13 heme 13 controlled study 12 nonhuman 12 5 aminolevulinate synthase 11 Animal 11 Animals 11 Heme 11 Kinetics 10 human 10 kinetics 10 5-Aminolevulinate Synthetase 9 Humans 9 Liver 9 liver 9 porphobilinogen synthase 9 Ammonia-Lyases 8 Porphobilinogen Synthase 8 aminolevulinic acid 8